Technical Field
This disclosure relates generally to electronic devices, and more particularly to portable electronic devices having proximity sensors.
Background Art
Proximity sensors detect the presence of nearby objects adjacent to a device in which the proximity sensors are disposed. Illustrating by example, some proximity sensors emit an electromagnetic or electrostatic field. A receiver then receives reflections of the field from the nearby object. The proximity sensor detects changes in the received field to detect positional changes of nearby objects based upon changes to the electromagnetic or electrostatic field resulting from the object becoming proximately located with a sensor.
Electronic devices employ proximity sensors in different ways. In one application, a device may use a proximity sensor to manage power consumption of audio and video devices. For example, a proximity sensor may detect that a device is adjacent to a user's face, such as when the user is using the device for a telephone call. When this occurs, the device may turn OFF the display to save power. In another example, when a device determines that a user's face is adjacent to the device, the device may reduce speaker volume so as not to over stimulate the user's eardrums.
Prior art proximity detectors suffer from several issues. First, they generally work at only a very close range. Accordingly, an object may need to be within, say, five millimeters of a proximity detector to be properly detected. Second, proximity sensors only detect objects within a small area about the proximity sensor itself. Consequently, the use of one or two proximity sensors on an electronic device creates “blind spots” in which objects may not be detected. It would be advantageous to have an improved proximity detection apparatus and method.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present disclosure.